"Don't get discouraged. If you want piece of good advice do as I do and count your fish in December.There will be plenty of ups and downs during the season."
Best bit of advice I've seen on fishing.
He that would make his own liberty secure, must guard even his enemy from oppression; for if he violates this duty, he establishes a precedent that will reach to himself.
Thomas Paine
When I get in a bad slump I find the best thing to do is take a few days off. It clears my head and gives me time to think about what I'm doing wrong. Then when I go back I'm fresh and more willing to try new things.